3 ms·

I wish they would finally find a solution that actually fixes USB storage sync lockups. Whatever USB storage you use and whether USB2 or USB3, it's very easy to

by cm3 10y ago

I wish they would finally find a solution that actually fixes USB storage sync lockups. Whatever USB storage you use and whether USB2 or USB3, it's very easy to lock up a machine when data is flushed and is slow to do so. Given all the asynchronicity in the kernel, it's surprising there's such a Windows-like global wait-until-I'm-finished unresponsiveness bug.

_wmd 10y ago
I've never experienced the entire machine locking up before (going back 10+ years), only IO becoming severely locked up when writeback can't keep up with new IO, and always happened on non-USB media too.
- cm3 10y ago
  Xorg becomes totally unresponsive and I cannot switch to a VT, so I assume it's a global lock somewhere.
  - fit2rule 10y ago
    while sleep 10 do ; cat /proc/meminfo | grep Dirty ; done Watch the dirty cache data when this is happening, if you want to know for sure. Put a couple "sync;sync;sync"'s &&'ed on that cat, if you want to watch stimulating behaviour.. (More often than not, its the device. Linux is dealing with it fine.)
    - cm3 10y ago
      As I wrote above, the device is taking long to finish the flush operation, and that's nothing special, but making the machine not react to input and actually block everything else like, say, the network stack and thereby interrupt downloads, is not what I perceive as fine.
      - johnp_ 10y ago
        Which scheduler are you using on the USB device? Did you try deadline or BFQ? There is a long standing (CFQ-related) kernel issue causing system lockups in high I/O situations: https://bugzilla.kernel.org/show_bug.cgi?id=12309 https://bugzilla.kernel.org/show_bug.cgi?id=12309
        digi_owl 10y ago
        That second to last comment from Tashnikov is highly interesting, as i have noticed Firefox triggering a virtual lockup on Android when started.
        deleted 10y ago
        [deleted]
        cm3 10y ago
        Impossible to understand why BFQ isn't available as an option, when there are competing options for many things in the upstream kernel already.
        digi_owl 10y ago
        The most likely reason is a clash of personalities.
        cm3 10y ago
        Linus manages the kernel and should decide to include it as BFQ is just another option in a pluggable subsytem. BFQ is arguably more important than many things because it fixes bad performance and unresponsive behavior. I hope it's not that Jens Axboe has too much influence because he's the block layer maintainer.
        cm3 10y ago
        http://algo.ing.unimo.it/people/paolo/disk_sched/ http://algo.ing.unimo.it/people/paolo/disk_sched/ https://lwn.net/Articles/601799/ https://lwn.net/Articles/601799/

by cm3 10y ago

_wmd 10y ago

I've never experienced the entire machine locking up before (going back 10+ years), only IO becoming severely locked up when writeback can't keep up with new IO, and always happened on non-USB media too.

cm3 10y ago
Xorg becomes totally unresponsive and I cannot switch to a VT, so I assume it's a global lock somewhere.
- fit2rule 10y ago
  while sleep 10 do ; cat /proc/meminfo | grep Dirty ; done Watch the dirty cache data when this is happening, if you want to know for sure. Put a couple "sync;sync;sync"'s &&'ed on that cat, if you want to watch stimulating behaviour.. (More often than not, its the device. Linux is dealing with it fine.)
  - cm3 10y ago
    As I wrote above, the device is taking long to finish the flush operation, and that's nothing special, but making the machine not react to input and actually block everything else like, say, the network stack and thereby interrupt downloads, is not what I perceive as fine.
    - johnp_ 10y ago
      Which scheduler are you using on the USB device? Did you try deadline or BFQ? There is a long standing (CFQ-related) kernel issue causing system lockups in high I/O situations: https://bugzilla.kernel.org/show_bug.cgi?id=12309 https://bugzilla.kernel.org/show_bug.cgi?id=12309
      - digi_owl 10y ago
        That second to last comment from Tashnikov is highly interesting, as i have noticed Firefox triggering a virtual lockup on Android when started.
      - deleted 10y ago
        [deleted]
      - cm3 10y ago
        Impossible to understand why BFQ isn't available as an option, when there are competing options for many things in the upstream kernel already.
        digi_owl 10y ago
        The most likely reason is a clash of personalities.
        cm3 10y ago
        Linus manages the kernel and should decide to include it as BFQ is just another option in a pluggable subsytem. BFQ is arguably more important than many things because it fixes bad performance and unresponsive behavior. I hope it's not that Jens Axboe has too much influence because he's the block layer maintainer.
      - cm3 10y ago
        http://algo.ing.unimo.it/people/paolo/disk_sched/ http://algo.ing.unimo.it/people/paolo/disk_sched/ https://lwn.net/Articles/601799/ https://lwn.net/Articles/601799/